Blog Archive

Monday, 31 March 2008

Weekly BioNews 24 - 31 Mar 2008

- Stem Cells From Hair Follicles May Help 'Grow' New Blood Vessels

ScienceDaily (Mar. 29, 2008)

For a rich source of stem cells to be engineered into new blood vessels or skin tissue, clinicians may one day look no further than the hair on their patients' heads, according to new research published earlier this month by University at Buffalo engineers.

"Engineering blood vessels for bypass surgery, promoting the formation of new blood vessels or regenerating new skin tissue using stem cells obtained from the most accessible source -- hair follicles -- is a real possibility," said Stelios T. Andreadis, Ph.D., co-author of the paper in Cardiovascular Research and associate professor in the Department of Chemical and Biological Engineering in the UB School of Engineering and Applied Sciences.

Researchers from other institutions previously had shown that hair follicles contain stem cells.

Research by Stelios Andreadis has produced this smooth muscle progenitor cell derived from a hair follicle, which expresses calponin (in red), a marker for smooth muscle cells. The cell nucleus is shown in blue.

Biologists at Purdue University have determined why dengue virus particles undergo structural changes as they mature in host cells and how the changes are critical for enabling the virus to infect new host cells.

The findings pertain to all viruses in the family of flaviviruses, which includes a number of dangerous insect-borne diseases such as dengue, West Nile, yellow fever and St. Louis encephalitis. Dengue is prevalent in Southeast Asia, Central America and South America. The virus, which is spread by mosquitoes, infects more than 50 million people annually, killing about 24,000 each year, primarily in tropical regions.

The researchers detailed critical changes that take place as the virus is assembled and moves from the inner to the outer portions of its host cell before being secreted so that it can infect other cells. Virus particles are exposed to progressively less acidic conditions as they traverse this "secretory pathway," and this changing acidity plays a vital role in the maturation of the virus.

This composite shows an image of the dengue virus, top left, taken with cryoelectron microscopy, and, to the right of that image are reconstructions of how virus particles mature as they move through their host cells. Purdue biologists have determined why the virus undergoes structural changes as it matures in host cells and how the changes are critical for enabling the virus to infect new host cells. Other elements of the composite show structural details of the virus and a vital component made of two linked proteins called precursor membrane protein and envelope protein.

The production of complex, multicellular tissues such as skin or blood vessels can now be envisaged, thanks to the development of a bioreactor with a "decoy effect", by scientists in the "Ingénierie des matériaux polymères" Unit(1) (CNRS / University of Lyon 1/ University of Saint-Etienne / Insa Lyon). This novel, patented bioreactor enabling the culture and co-culture of cells of different types is a world first. The team's work was published in Nature on March 6, 2008.

Living materials can be considered as complex physical hydrogels. This means that they are mainly made up of a network of polymer chains imprisoning a very high proportion of water (80% of net weight, for example, in joint cartilage) and living cells which generate this polymer network. Furthermore, many living tissues comprise several layers of gels containing different cells, and the latter cannot move freely within a layer, and still less from one layer to another.

Using this observation as their starting point, a team in the "Ingénierie des matériaux polymères" Unit, IMP, (CNRS /University of Lyon 1/ University of Saint-Etienne/ Insa Lyon) has developed novel, physical, multi-membrane hydrogels that act as "decoys" for biological media. These biomaterials can adopt many different shapes (spheres, disks, tubes, etc.) and may have numerous biomedical applications. They could be used directly as implants, but also constitute new-generation bioreactors because of their multi-membrane structure.

Example of the multimembrane spheroid structure (chitosan hydrogel), observed from a circumferential section, showing the separation of membranes in the structure.

Researchers in Colombia, South America, describe a new strategy for designing the next generation of synthetic vaccines that could lead to more effective treatments for fighting malaria, tuberculosis, AIDS and other infectious diseases. These conditions kill more than 17 million people around the world each year.

Traditional vaccine development involves the use of microorganisms to trigger an immune response by the body. However, this approach can produce unwanted side effects and may be ineffective against microbes with extremely complex infection cycles. Therefore, researchers agree on the need for better vaccine.

In the study, Manuel E. Patarroyo and his son Manuel A. Patarroyo describe a completely new strategy for designing more effective vaccines, which are chemically synthesized in the laboratory without the use of microorganisms. They identified dozens of key protein fragments involved in the complex infection process of the malaria parasite, from which they designed, specifically modified and synthesized chemically some of the most promising malaria vaccine candidates that have been tested to date.

LONDON (Reuters) - U.S. and European scientists have found six more genes that make people more susceptible to developing type 2 diabetes, in a study they say may help prevent and treat the chronic condition.

The finding extends the total number of genes linked to the disease to 16 and provides clues to how the biological mechanisms that control blood sugar levels go awry when people get type 2 diabetes, the researchers said.

"None of the genes we have found was previously on the radar screen of diabetes researchers," said Mark McCarthy, a diabetes researcher at the University of Oxford, who co-led the study."Each of these genes therefore provides new clues to the processes that go wrong when diabetes develops, and each provides an opportunity for the generation of new approaches for treating or preventing this condition."